Electric Trike WAT - Wooden Aluminum ETrike

The main goal of this project is to propose a light three-wheeled electric vehicle which first of all has the characteristic of being able to be built and assembled without the aid of welding (except some parts of the rear swingarm), exclusively through the tightening of screws and bolts. With this assembly technique it is also possible to make chassis for single-seaters sports car with electric motor, this will be the next project (see SSeRC_1 pdf).

Another important goal is also to pursue the respect for the environment by using recyclable materials such as wood, with which a large part of the chassis is made, aluminum, iron and plastic (nylon).

This version presented on Instructable is exclusively the chassis of a tricycle on which it is possible to set up a bodywork according to one's needs, a bodywork that can be made with different materials such as ABS, thermoformable plastics, 4/10 thick aluminium or a 3D printed bodywork that can be supplied with the kit and showed in these pitcures.

Furthermore, it is possible to set up the trike with an electric in-wheel motor (electric wheel-hub) or the chain transmission with brushed electric motor, the version with the chain transmission is shown here.

The variable length of the vehicle is mainly due to dynamic needs in which there is a need to respect certain sizes to possibly avoid the vehicle from overturning when cornering; furthermore, the space in the rear area offers the possibility of accommodating a second person or even a load compartment of adequate dimensions for the available space (mini urban cargo solution).

In this context we don’t deal with the topic of the approval that may be necessary for road circulation; the vehicle approval, if necessary, depends on the laws in force in each country.

The tricycle kit can be supplied (even assembled if need), here is essentially to propose the project and the idea of the chassis.

A possible offer of collaboration with a company willing to industrialize and market the "WAT tricycle" is evaluated.

LIST OF MATERIALS

1 – Marine plywood, 25mm thick (surface used: 80cm x 80cm), see cutting from dwgs

2 - Aluminum pipe 25x3mm, length 115cm, n.2 pieces

3 - Aluminum pipe 25x3mm, length 175cm, n.2 pieces

4 - Steel pipe 20x2mm, length 115cm, n.4 pieces

5 - Rectangular iron tube 40x10x1.5mm, n.2 pieces and square iron tube 15x2

8 - Structural pieces in folded sheet metal of various thicknesses (see drawings)

9 - Mechanical components : M10 and M8 threaded bars, clamping elements and various small parts, MISUMI furniture

10 – Bike handlebar

11 – Handlebar column attachment (steel pipe 20x1)

12 – Handlebar brake lever

13 – Rear shock absorber L=190mm n.1 piece

14 – Front shock absorber L=125mm n.2 pieces

15 – 20” rear wheel in light alloy and disc brake

16 – z44 tooth driven sprocket

17 – Chain L= 840mm (as function of motor type, position, drive and driven sprocket)

18 – Knob accelerator

19 – 36V control unit – 800/1000W

20 – 36V - 1000W brush motor with 13z drive sprocket

21 – Rechargeable Li-Po battery – 36V-5.2 Ah (in this version)

22 – Cables and terminals

We start with the plywood boards (n.1 – LIST MAT.) that need to be cut and drilled (Fig.1) as from drawing, see example of one pdf/dxf drawings list (Fig.2-4-5-6); in the event that it is possible to make a laser or mill cut, the cutting will be more precise for the benefit of a better assembly; the DXF drawings of the various wooden parts are used, they are 4 dwgs and 7 plywood boards in total (Fig.3-56-57 for boards type.

Trace to measure (Fig.3 dimensions) the positioning of the various wooden components (plywood wooden crossbars) and the threaded holes of aluminum and iron pipes (n.2-3-4 – LIST MAT.) suitable for fixing the wooden components themselves using M6x40 screws, taking care to create a blind hole on plywood crossbar (Fig.9b) to house the head of the screw itself (Fig. 4-5-6-7-8-9).

Once the chassis made up of aluminum structural pipes has been assembled, we move on to assembling the mechanical components and the structural pieces in folded sheet metal such as the assembly that makes up the steering box which is been assembled before being painted (Fig.10) in order to test the exact functionality (Fig.11-12-13-14), see example of pdf/dxf drawings list (Fig.15).

The universal joint (MISUMI UNCA20 - Fig.22) and the two bearing holders (n.2 MISUMI BEARINGS HBTP20 - Fig.23) are then mounted (Fig.16-17-18) with the two 20x1.2 pipes already cut to size and which make up the steering column (Fig.19-20); the steering geometry will be very important.

In the lower side of the 20x1.2 tube steering column, a bracket made of flat steel elements will be fixed to which the steering tie rods will be fixed through M8 ball joints (Fig. Fig.21); see Fig.3 dimensions to size steering column.

Before fixing the front wooden component (plywood board crossbar) it is necessary to complete the assembly of what concerns in order the footrest bracket (see Fig.28-29), the steering and the front suspensions, the latter made with wishbone arms composed of 3mm thick metal plates (Fig.22-23-24-25) and fixed to the chassis by steel shaft collars (n.20 MISUMI KSC2012 - Fig.45) with the same internal diameter as the 20x2 tube and equipped with an allen screw to prevent it from sliding inside the tube itself, see example of pdf/dxf drawings list (Fig.26-27).

Therefore, in order, the following metal plates elements will be inserted into the lower tubes 1, 2, 3 and 4 : footrest bracket (Fig.28 and pdf/dxf dwg Fig.29) locked with n.2 MISUMI KSC2012 and n.2 MISUMI KSC2512 (Fig.46) shaft collars (to lower aluminum 25x3 pipes), steering box made up of universal joints and the respective bearings n.2 MISUMI HBTP20 that we have already assembled, upper and lower flat wishbones (rear) of the suspension, front shock absorber support (Fig.30 and pdf/dxf dwg Fig.31), also made of 4mm flat bar metal, with the relative collars.

It is important to remember that lubricated Teflon bushings washers are installed inside the holes of the the wishbones bars that make up the front suspension (n.8 MISUMI GFM-2023-07 - Fig.47).

To complete the front suspension there is the assembly of the front shock absorbers (n.13 MAT. LIST) fixed with M8 screws to the shock absorber support and to the lower arm (Fig.32-33).

Once the 25mm thick. wooden structural component (plywood board crossbar) has been mounted to close the front of the chassis (pdf/dxf dwg Fig.34), the front wheel hub are mounted on the appropriately sized wheel hub holders in order to create a geometry suitable for obtaining the characteristic angles of the steering and the suspension itself (caster, camber, trail and scrub radius) (Fig.35-36-43), see example of pdf/dxf drawings list (Fig.37 - 4 pcs).

The handlebar is mounted using its column attachment (Fig.44-44B)

For the wheel hub you can use a wheel hub for 100cc karts (sk1075 right and sk1075 left - Fig.42) with a diameter of 17mm and an inclination of 10°, it involves adapting the hub of the 20" wheel of a bicycle by inserting the appropriate bearings or using an alloy wheel with the 17mm hub (Fig.38-39-40-41).

Furthermore, the kart spindle has already welded the bracket for the steering tie rods which otherwise would have to be built from scratch; here are linked the tie rods steering obtained from M8 threaded rod and two ball joints (n.4 MISUMI PHSC 8 - Fig.48); the wheel hub or kart spindle (Fig.49) it is usually supplied with all the pin (Fig.50), washers (Fig.51) nuts (Fig.52), bushings (Fig.53) and bearings (Fig.54).

In Fig.55-56-57 the front axle and plywood board assemblies are summarized with numbered parts :

1 - plywood board - crossbar (Fig.4);

2 - plywood board - crossbar (Fig.2);

3 - plywood board - crossbar (Fig.5);

4 - plywood board - crossbar (Fig.6);

5-17 - steering box (Fig.15)

6-7 - upper and lower suspensions wishbones (Fig.26-27)

8 - lower shock support (8mm diameter bar)

9 - wheel hub-spindle (Fig.49)

10-11 - hub holders (knuckle) (Fig.37)

12 - upper shock support (Fig.31)

14 - ball joint (Fig.48)

15 - steering tie rod (M8 threaded bar)

16-18 - upper and lower steering column (22x1 steel pipe)

19 - steering steel bracket (Fig.21)

20 - footrest bracket (Fig.29)

24-25 - shaft collars, diam.20 and 25mm (Fig.45-46)

26 - front shock absorbers (n.14 LIST OF MATERIAL)

27 - handlebar (fIG.44B)

28 - steering column bearings (Fig.23)

29 - universal joint (Fig.22)

30 - aluminum pipe 25x3mm (n.2-3 LIST OF MATERIAL)

31 - steel pipe 20x2mm (n.4 LIST OF MATERIAL)

32 - M10 threaded bar

In the rear area we have the wheel suspension system consisting of a swingarm and mono shock absorber n.13 MATERIAL LIST, also in this case the linkages have been designed to obtain suitable comfort of the vehicle itself, see dwgs (see Fig.58)

To connect the swingarm to the chassis, a 3 mm thick folded plate metal support was created, suitably drilled for connection to the rear wooden member (plywood board crossbar) and to the swingarm itself (Fig.59-60) the same system was adopted for connecting the shock absorber head to the chassis and to the rocker arm system, (Fig.61-62); a M10 threaded bar link the swingarm to the folded metal support (Fig.61).

The swingarm is made up of two 40x10x1.5mm rectangular iron tubes (Fig.63-64) to which is connected a 15x2mm welded square tube to create a fork (Fig.65-67), in addition has been created a connection for the rocker-shock system by a 3mm thick folded plate metal support (Fig.66), see the assembly swingarm in Fig.68-69; in addition to it, the disc brake caliper (Fig.63) was fixed with two M4x20 bolts.

Furthermore, on the swingarm there is the lower support of the shock absorber made with 2mm thick folded plate elements connected between the two arms; the fork supports are also welded onto the swingarm which acts on the head of the mono shock absorber via a rocker arm (Fig.69). All these linkages could be designed and built according to the type of shock absorber and the comfort you want to obtain.

Also a structural simulation (fem analysis) has been made for the rear swingarm and fork (Fig.70); a 3D printed nylon-carbon fiber version (fem analysis tested) can also be adapted (Fig.70B).

Depending on the width of the wheel it is also possible to adopt a commercial version of the swingarm used expecially on pit bikes (Fig.70C-70D)

This version of the trike is equipped with an electric motor with chain transmission (Fig.71) but with appropriate modifications to the rear swingarm it is possible to fit a wheel hub motor (Fig.74); the assembly of the rear alloy wheel with 20"x2.50" tire is carried out by inserting the hub of the wheel itself into the slots appropriately obtained in the swingarm, the driven sprocket mounted on the wheel provides for the connection of the chain to the motor for motion transmission (Fig.72).

The chain tension is setting up by the chain tensioner located at the end of the swingarm (Fig.71-72).

In Fig.75-76-77 the rear suspension assembly is summarized with numbered parts :

21 - folded plate metal swingarm support (Fig. 59-60)

22-23 - shock absorber upper support (Fig.61-62)

24 - shaft collars, diam.20 (Fig.45)

34 - rear swingarm, no fork showed.

The electrical components that are part of the trike propulsion system are the motor (Fig.78), the control unit (Fig.79), the accelerator on handlebar (of a normal ebike) and the batteries (Fig.79), the latter located inside the frame as well as the control unit, all appropriately wired and connected and possibly cooled.

As told before this's a version with brushed motor and chain transmission thus here're showed electrical components suitable for this type of equipment :

1) 1000W brushed motor, 36V

2) 36V - 5Ah battery

3) 36V handlebar throttle (electric bike)

4) 36V - 35A controller for brushed motors

Anyway in this trike is possible to mount any type of accessories like a digital display (Fig.80); this is a tricycle that lends itself to different configurations, like a cargo bike, for exampe.

As previously described, the bodywork can take on various shapes and configurations depending even on how the wooden boards are shaped. In this example here showed a 3D printed bodywork in polymeric material (nylon) are proposed (A and B version), the versions of which are those represented in these renderings.

Here is not showed but the bodywork parts are fixed with screws to the wooden plywood boards which have metal inserts screwed in the wood (Fig.81-82-83-84).

Furthermore, some photos of the assembled frame and some drawings of the frame itself are shown in pdf files.